Heater for surgical viewing instruments

ABSTRACT

A system and associated method is used for warming an endoscope, laparoscope, or other such instrument to minimize fogging. The preferred embodiment comprises a pad for wrapping around an instrument, including a one or more substances operative to generate heat through an exothermic reaction; and an activation disc located around the periphery of the pad to provide for convenient user access. In the preferred embodiment, the activator is a mixture of water and sodium acetate, and the disc is made of perforated stainless steel. A housing contains the pad in sleeve form and an optional heat-conductive tube to receive the instrument around which the pad is wrapped. The pad may be partitioned.

REFERENCE TO RELATED APPLICATION

This application claims priority from U.S. Provisional PatentApplication Ser. No. 60/463,642, filed Apr. 17, 2003, the entire contentof which is incorporated herein by reference.

FIELD OF THE INVENTION

This invention relates generally to surgical instruments and suppliesand, in particular, to heater for medical and surgical viewers subjectto fogging.

BACKGROUND OF THE INVENTION

In minimally invasive surgical (MIS) procedures, elongated illuminatorsand viewers, i.e., laparoscopes and endoscopes, are inserted throughsmall incisions in the abdominal wall or elsewhere. The viewer istypically coupled to a video camera that shows the operating field on amonitor.

A common problem is that the lens on the viewer becomes fogged. When theviewer is inserted, the lens is typically at operating room temperaturewhich is often much colder than room temperature. The body cavity is atbody temperature and high humidity. As such, water droplets condense onthe lens, obscuring the view. When the lens fogs, the surgeon mustremove the instrument, clean the lens, and reinsert the instrument atwhich time fogging often begins again.

To address this problem, the instrument may be immersed in a warm salinebath before surgery and during cleaning. This can be time-consuming andit is difficult to control temperature to consistent, effective workingtemperature.

An automated approach is described in Published U.S. Patent Application2002/0022762 A1. A lens warming and cleaning device for use with anoptical surgical instrument is disclosed. The device includes aheat-conducting tube sized and shaped to receive the lens portion of theinstrument, a heating element thermally coupled to an exterior of thetube, and a cleaning member disposed within the tube. The cleaningmember is disposed such that when the lens portion of the instrument isinserted into the tube, the lens portion contacts the cleaning member.

The heating element comprises a flexible pad that surrounds at least aportion of the tube including the lens portion. The pad may be wrappedaround tube or attached to tube using an adhesive or hook-and-loopfasteners.

In one disclosed embodiment, the heating pad includes a flexible,air-permeable outer bag that encases a chemical mixture that generatesan exothermic reaction when activated. The chemical mixture can be,e.g., a mixture of iron powder, water, cellulose, vermiculite, activatedcarbon, and salt. Exposing the mixture to atmospheric oxygen triggers anexothermic reaction that warms the pad to a temperature of about 60° C.and sustains that temperature for about six hours.

Other types of known exothermic reaction mixtures can be used. Forexample, the mixture can consist of iron powder, a chloride or sulfateof a metal having a tendency of ionization greater than iron, activecarbon, and water. Alternatively, the chemical mixture can be asuper-cooled, supersaturated aqueous solution of sodium acetate. The padcan also employ other types of exothermic chemical reactions to generateheat, or it can include a resistance heater powered by, e.g., a batteryor an external source of electricity.

The problems with this system are two-fold. First, the addition of acleaning mechanism is all embodiments constitutes an unnecessarycomplication, since warming is by far the greatest need. Additionally,although “other types of exothermic chemical reactions” are mentioned inpassing, activation methods and apparatus are not disclosed.Accordingly, the need remains for a less expensive yet effectiveendoscope/laparoscope warming system.

SUMMARY OF THE INVENTION

This invention resides in a system and associated method for warming anendoscope, laparoscope, or other such instrument to minimize fogging.The preferred embodiment comprises a pad for wrapping around aninstrument, including a one or more substances operative to generateheat through an exothermic reaction; and an activation disc locatedaround the periphery of the pad to provide for convenient user access.In the preferred embodiment, the activator is a mixture of water andsodium acetate, and the disc is made of perforated stainless steel. Ahousing contains the pad in sleeve form and an optional heat-conductivetube to receive the instrument around which the pad is wrapped. The padmay be partitioned.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a drawing which shows the way in which a heating pad isinserted into a housing with the top cover removed;

FIG. 2 shows the way in which an internal tube is placed into the pad;

FIG. 3 is a drawing which shows how the pad is then folded over on topof the tube to completely surround it;

FIG. 4 illustrates the addition of the top cover without a hinge lid;

FIG. 5 is the drawing of a completed unit including a hinge lid;

FIG. 6 is a drawing of the preferred embodiment the pad; and

FIG. 7 is a drawing illustrating an alternative embodiment of a pad.

DETAILED DESCRIPTION OF THE INVENTION

This invention improves upon the prior art by providing a low-cost yeteffective heater for medical/surgical viewers subject to fogging,including endoscopes, laparoscopes, elongated microscopes, and so forth.Broadly, the apparatus includes a housing into which there is disposed aheating pad containing chemicals to produce heat through an exothermicreaction. The pad is rolled in the housing to create an elongated cavityin alignment with an aperture through the housing into which theinstrument to be warmed is placed. In a preferred embodiment, aheat-conductive tube is also included between the rolled pad andinstrument to provide for more consistent heating, and silicon acetateis used as the active ingredient in the pad, generated heat throughcontact with water also in the pad.

Now making reference to the drawings, FIG. 1 is an obliquerepresentation showing the way in which pad 102 is placed into a housing104 without a lid or hinged access panel, which will be described withreference to subsequent figures. In FIG. 2, a heat-conductive tube 120of aluminum, stainless steel, or other suitable metal or other materialis placed into the partially rolled pad 102.

In FIG. 3, the remaining portion of the pad 102 is folded over and ontothe tube 120, again, without the lid or access panel being shown. InFIG. 4, the lid 140 is placed onto the housing, with an access door 142being provided in alignment with the opening of tube 120, as shown. InFIG. 5, a hinged lid 150 is added, allowing a user to open the lid togain access to an activation area 152 on the pad, which will bedescribed in further detail below.

FIG. 6 is a plan view of a preferred heating pad 160 according to theinvention. The pad contains a mixture of sodium acetate and water, and,unique to the invention, a particular spot 152 is provided, including astainless steel disc to initiate the chemical reaction. Referring backto FIG. 5, this disc is placed on the pad so that when rolled into thehousing, the area 152 is easily accessible when the hinged lid 150 isopened. Note that the pad 160 is also otherwise partitioned along lines164 and 166 to conveniently provide fold areas for easier placement intothe housing 104. Gaps 168, 170 facilitate fluid transfer of the mixture.

FIG. 7 illustrates an alternative design for the pad, wherein, insteadof elongated seams 164 and 166, islands 174 and 176 are providedinstead, these also being conducive to folding along the same desiredline.

1. A system for warming an endoscope, laparoscope, or other suchinstrument to minimize fogging, comprising: a flexible pad having alength, a width and a periphery for wrapping around the instrument, thepad including a mixture of water and sodium acetate to generate heatthrough an exothermic reaction; an activation disc located around theperiphery of the pad; and one or more elongate partitions runninglengthwise along the pad to establish fold lines, each partitionincluding a gap to facilitate fluid transfer of the mixture.
 2. Thesystem of claim 1, wherein the activation disc is made of perforatedstainless steel.
 3. The system of claim 1, further including a housingto contain the pad in sleeve form into which the instrument is inserted.4. The system of claim 1, further including a heat-conductive tube toreceive the instrument around which the pad is wrapped.